feat: adds Lesson 13 content and assignment

lesson_13/README.md

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+# Lesson 13
+
+## Homework
+
+* Complete [Applying SOLID principles](#applying-solid-principles-bank-atm) exercise.
+
+## Applying SOLID Principles (Bank ATM)
+
+Your task for this assignment is add enhancements to an ATM simulator. The [BankAtm][bankatm-file] is at the center of the model, allowing us to add one or more `CheckingAccount` instances and make withdrawals or deposits via cash or check. You will need to implement at least two of the following functional enhancements to the `BankAtm` class WITHOUT adding a new method. Note that you can update existing methods, however.
+
+### Functional Requirements
+
+* We want to support a `SavingsAccount` that works just like the `CheckingAccount`, but doesn't allow you to write checks against the account.
+* We want the `BankAtm` class to support the concept of a `BusinessCheckingAccount`. A business account requires that at least one of the owning accounts is a business.
+* In addition to supporting checks and cash, we also want to support the concept of another monetary instrument called a `MoneyOrder`. Unlike a `Check`, a `MoneyOrder` withdraws funds from a source account immediately on creation for the purposes of this simulation..
+* For traceability, all of the transactions in the `BankAtm` class should logged. Create an `AuditLog` class that keeps a record of all debits and credits to any account and integrate it with the `BankAtm` class. 
+* For the `depositFunds` method that accepts a cash amount, we'd like the ability to deposit funds in a variety of currencies. Add a parameter that accepts a currency type and a new object that encapsulates the currency converter logic for converting a cash amount to the account currency type.
+
+### Technical Requirements
+
+* You must integrate new features into the `BankAtm` without adding a new public method. Existing public methods may be modified without breaking existing functionality.
+* You must update the `BankAtm` tests and may modify or add other applicable tests.
+* Feel free to add the minimal number of classes, interfaces, or abstract classes needed to fulfill each requirement.
+* You must update existing javadocs and may add new documentation for new types and methods you introduce.
+
+[bank-folder]: ./bank/
+[bankatm-file]: ./bank/bank_app/src/main/java/com/codedifferently/lesson13/bank/BankAtm.java

lesson_13/bank/.gitattributes

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+#
+# https://help.github.com/articles/dealing-with-line-endings/
+#
+# Linux start script should use lf
+/gradlew text eol=lf
+
+# These are Windows script files and should use crlf
+*.bat text eol=crlf
+

lesson_13/bank/.gitignore

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+# Ignore Gradle project-specific cache directory
+.gradle
+
+# Ignore Gradle build output directory
+build

lesson_13/bank/bank_app/build.gradle.kts

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+plugins {
+ // Apply the application plugin to add support for building a CLI application in Java.
+ application
+ eclipse
+ id("com.diffplug.spotless") version "6.25.0"
+ id("org.springframework.boot") version "3.2.2"
+ id("com.adarshr.test-logger") version "4.0.0"
+}
+
+apply(plugin = "io.spring.dependency-management")
+
+repositories {
+ // Use Maven Central for resolving dependencies.
+ mavenCentral()
+}
+
+dependencies {
+ // Use JUnit Jupiter for testing.
+ testImplementation("com.codedifferently.instructional:instructional-lib")
+ testImplementation("org.junit.jupiter:junit-jupiter:5.9.1")
+ testImplementation("org.springframework.boot:spring-boot-starter-test")
+ testImplementation("org.assertj:assertj-core:3.25.1")
+ testImplementation("at.favre.lib:bcrypt:0.10.2")
+
+ // This dependency is used by the application.
+ implementation("com.codedifferently.instructional:instructional-lib")
+ implementation("com.google.guava:guava:31.1-jre")
+ implementation("com.google.code.gson:gson:2.10.1")
+ implementation("org.projectlombok:lombok:1.18.30")
+ implementation("org.springframework.boot:spring-boot-starter")
+}
+
+application {
+ // Define the main class for the application.
+ mainClass.set("com.codedifferently.lesson13.Lesson13")
+}
+
+tasks.named<Test>("test") {
+ // Use JUnit Platform for unit tests.
+ useJUnitPlatform()
+}
+
+
+configure<com.diffplug.gradle.spotless.SpotlessExtension> {
+
+ format("misc", {
+ // define the files to apply `misc` to
+ target("*.gradle", ".gitattributes", ".gitignore")
+
+ // define the steps to apply to those files
+ trimTrailingWhitespace()
+ indentWithTabs() // or spaces. Takes an integer argument if you don't like 4
+ endWithNewline()
+ })
+
+ java {
+ // don't need to set target, it is inferred from java
+
+ // apply a specific flavor of google-java-format
+ googleJavaFormat()
+ // fix formatting of type annotations
+ formatAnnotations()
+ }
+}

lesson_13/bank/bank_app/src/main/java/com/codedifferently/lesson13/Lesson13.java

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+package com.codedifferently.lesson13;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.context.annotation.Configuration;
+
+@Configuration
+@SpringBootApplication(scanBasePackages = "com.codedifferently")
+public class Lesson13 {
+
+ public static void main(String[] args) {
+ var application = new SpringApplication(Lesson13.class);
+ application.run(args);
+ }
+}

lesson_13/bank/bank_app/src/main/java/com/codedifferently/lesson13/bank/BankAtm.java

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+package com.codedifferently.lesson13.bank;
+
+import com.codedifferently.lesson13.bank.exceptions.AccountNotFoundException;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Set;
+import java.util.UUID;
+
+/** Represents a bank ATM. */
+public class BankAtm {
+ private final Map<UUID, Customer> customerById = new HashMap<>();
+ private final Map<String, CheckingAccount> accountByNumber = new HashMap<>();
+
+ /**
+ * Adds a checking account to the bank.
+ *
+ * @param account The account to add.
+ */
+ public void addAccount(CheckingAccount account) {
+ accountByNumber.put(account.getAccountNumber(), account);
+ account
+ .getOwners()
+ .forEach(
+ owner -> {
+ customerById.put(owner.getId(), owner);
+ });
+ }
+
+ /**
+ * Finds all accounts owned by a customer.
+ *
+ * @param customerId The ID of the customer.
+ * @return The unique set of accounts owned by the customer.
+ */
+ public Set<CheckingAccount> findAccountsByCustomerId(UUID customerId) {
+ return customerById.containsKey(customerId)
+ ? customerById.get(customerId).getAccounts()
+ : Set.of();
+ }
+
+ /**
+ * Deposits funds into an account.
+ *
+ * @param accountNumber The account number.
+ * @param amount The amount to deposit.
+ */
+ public void depositFunds(String accountNumber, double amount) {
+ CheckingAccount account = getAccountOrThrow(accountNumber);
+ account.deposit(amount);
+ }
+
+ /**
+ * Deposits funds into an account using a check.
+ *
+ * @param accountNumber The account number.
+ * @param check The check to deposit.
+ */
+ public void depositFunds(String accountNumber, Check check) {
+ CheckingAccount account = getAccountOrThrow(accountNumber);
+ check.depositFunds(account);
+ }
+
+ /**
+ * Withdraws funds from an account.
+ *
+ * @param accountNumber
+ * @param amount
+ */
+ public void withdrawFunds(String accountNumber, double amount) {
+ CheckingAccount account = getAccountOrThrow(accountNumber);
+ account.withdraw(amount);
+ }
+
+ /**
+ * Gets an account by its number or throws an exception if not found.
+ *
+ * @param accountNumber The account number.
+ * @return The account.
+ */
+ private CheckingAccount getAccountOrThrow(String accountNumber) {
+ CheckingAccount account = accountByNumber.get(accountNumber);
+ if (account == null || account.isClosed()) {
+ throw new AccountNotFoundException("Account not found");
+ }
+ return account;
+ }
+}

lesson_13/bank/bank_app/src/main/java/com/codedifferently/lesson13/bank/Check.java

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+package com.codedifferently.lesson13.bank;
+
+import com.codedifferently.lesson13.bank.exceptions.CheckVoidedException;
+
+/** Represents a check. */
+public class Check {
+ private final String checkNumber;
+ private final double amount;
+ private final CheckingAccount account;
+ private boolean isVoided = false;
+
+ /**
+ * Creates a new check.
+ *
+ * @param checkNumber The check number.
+ * @param amount The amount of the check.
+ * @param account The account the check is drawn on.
+ */
+ public Check(String checkNumber, double amount, CheckingAccount account) {
+ if (amount < 0) {
+ throw new IllegalArgumentException("Check amount must be positive");
+ }
+ this.checkNumber = checkNumber;
+ this.amount = amount;
+ this.account = account;
+ }
+
+ /**
+ * Gets the voided status of the check.
+ *
+ * @return True if the check is voided, and false otherwise.
+ */
+ public boolean getIsVoided() {
+ return isVoided;
+ }
+
+ /** Voids the check. */
+ public void voidCheck() {
+ isVoided = true;
+ }
+
+ /**
+ * Deposits the check into an account.
+ *
+ * @param toAccount The account to deposit the check into.
+ */
+ public void depositFunds(CheckingAccount toAccount) {
+ if (isVoided) {
+ throw new CheckVoidedException("Check is voided");
+ }
+ account.withdraw(amount);
+ toAccount.deposit(amount);
+ voidCheck();
+ }
+
+ @Override
+ public int hashCode() {
+ return checkNumber.hashCode();
+ }
+
+ @Override
+ public boolean equals(Object obj) {
+ if (obj instanceof Check other) {
+ return checkNumber.equals(other.checkNumber);
+ }
+ return false;
+ }
+
+ @Override
+ public String toString() {
+ return "Check{"
+ + "checkNumber='"
+ + checkNumber
+ + '\''
+ + ", amount="
+ + amount
+ + ", account="
+ + account.getAccountNumber()
+ + '}';
+ }
+}